The 300 South Wacker building has never been what anyone would call a sexy skyscraper. Its most conspicuously dull feature has always been the khaki-colored concrete elevator shaft in the center third of its riverside facade.

That changed with a makeover commissioned by Beacon Capital, the company that purchased the 445-foot-tall structure last year. In October, Beacon unveiled a giant mural that completely covers the drab beige slab on the west face of the tower. The piece is a map of the Chicago River and the surrounding streets—from Cermak to Chicago and LaSalle to Jefferson. The 300 South Wacker building itself appears on the mural’s map as a three-dimensional red block that’s backlit at night.

“The building was getting old and stale, and this was a very creative way to update it and add some value,” says Thomas Merkle, president of South Water Sign, which was paid $810,000 to create the work, a project that took three and a half months to complete. It was devised by Trip Kyle of ESI Design, a NYC-based firm that created similar installations at Beacon-owned properties around the country.

“The concrete wall was just like an old road—it required maintenance,” Merkle says. “We had to patch it and then acid-wash it to make sure the paint adhered properly.”

Beacon Capital’s renovation of 300 South Wacker also included a face-lift for the elevator lobby. Following Kyle’s design, a South Water crew used a water jet cutter to engrave maps of downtown locations into large sheets of stainless steel that replaced the lobby’s marble paneling. A $150,000 LED system backlights the maps with various colors. “It’s quite an eyeful,” Merkle boasts.